Sjaak Neefjes is professor Chemical Immunology at the Leiden University Medical Center and head of the department of Cell and Chemical Biology. Besides, he is, amongst others, a member of the Raad voor Aard- en Levenswetenschappen of KNAW and the Scientific Council Children Oncology (KiKa). In 2020 he received the NWO Spinoza Price which he uses to develop anti-cancer medication that work with minimal to no harmful side effects.